The MGM-140/-164/-168 Army Tactical Missile System (ATACMS) is a series of short-range, road-mobile, solid-propellant fueled, surface-to-surface ballistic missiles developed in the United States. The missile first saw use during the 1991 Persian Gulf War.

ATACMS Block 1

The ATACMS was designed to take over the conventional role of the MGM-52 Lance missile, providing tactical support to ground troops. The missile closely resembles its predecessor and is typically deployed from modified Multiple Launch Rocket System (MLRS) launch vehicles. There were a total of five variants planned, the standard Block 1, the extended-range Block 1A, an anti-hard target Block 1A variant, the terminated anti-tank Block 2, and a terminated nuclear version.¹

The Block 1 is the standard service version of the ATACMS. It is a tactical system designed to attack high-value targets of rear-echelon forces such as airfields, Surface-to-Air Missile (SAM) sites, artillery/missile forces, supply areas, and command groups. The large number of M74 submunitions saturates an enemy-held area and destroys both troops and equipment. The spread on the submunitions allows the ATACMS Block 1 to be used against moving military targets or against open facilities.

The M74 munitions used by the Block 1 are Anti-Personnel/Anti-Material (APAM) weapons. Each is a round ball with a diameter of 0.06 m and a weight of 0.59 kg. They are wrapped in a tungsten fragmenting wall with a steel casing and incendiary pellets.²

This allows the submunition to be highly effective against both personnel and equipment. The area of effect depends upon the height at which the submunitions are released, enabling either a large area of light damage or a small area of heavy damage. The munitions are ideal for the destruction of infantry and light equipment (communication gear, launch equipment, aircraft, support facilities, etc.), but are ineffective against anything heavily armored. The ATACMS Block 1 is launched from a modified version of MLRS M270 AVMRL (Armored Vehicle Multiple Rocket Launcher), which exchanges twelve MRLS rockets for two ATACMS Block 1 missiles. A single ATACMS Block 1 can also be carried and fired by a US Army HIMARS XM142 wheeled light vehicle. ³

The Block 1 has a range of 165 km and employs a single 560 kg warhead. This warhead is equipped with 950 M74 submunitions. The ATACMS Block 1 has an inertial guidance system that provides it an unknown level of accuracy; however, saturation of the area combined with the short-range of the missile provides a strong likelihood that the target will be successfully hit. The missile is 3.98 m long, 0.61 m wide and has a launch weight of 1,673 kg. It uses a single-stage solid propellant motor.

The ATACMS system ultimately derives from the 1978 ‘Assault Breaker’ technology demonstration program, which developed the concept of a ground launched guided missile equipped with guided submunitions. Formally begun as the Joint Tactical Missile System (JTACMS) in 1983, the program combined the Army’s Corps Support Weapon System and the Air Force Conventional Standoff Weapon programs. The testing phase for the ATACMS Block 1 was completed in December 1989 and the missile entered service in 1991 for use in the Persian Gulf War. In 1997, a total of 1,647 missiles had been ordered by the US Army and were in production.

The ATACMS Block 1 has been exported to several U.S. allies including: Bahrain, Greece, South Korea, Taiwan, Turkey, and the UAE. ⁴

As of 2009, it is believed that the Block 1 began a phase-out process, with no new orders being placed by the United States, though some foreign sales still occur.⁵

Spent Block 1 missiles are slated to be replaced by the Block 1A variant.

ATACMS Block 1A

The Block 1A has a minimum range of 100 km and deploys a single 160 kg warhead. The maximum range depends on the warhead, with 300 km for the submunition and 270 km for the unitary. This warhead can be equipped with 300 M74 submunitions, which are dispersed over the target area, or a unitary HE warhead. There are two different versions of single warhead versions, either for blast/fragmentation or for HE hard-target penetration. The ATACMS Block 1A uses an improved inertial guidance system combined with a Global Positioning Satellite (GPS). Given the improved guidance and the short range of the system, the accuracy for the unitary warhead is likely 10-50 m CEP, though the saturation from submunitions eliminates CEP as a concern. The missile is 3.98 m long, 0.61 m wide and has a launch weight of 1,321 kg. It uses a single-stage solid propellant motor.

The ATACMS Block 3, also designated as the TACMS-Penetrator, is an ATACMS Block 1A equipped with a Mk 4 reentry vehicle carrying a HE penetrating warhead. This variant has a range of 250 km.

The ATACMS Block 1A began testing in 1995 and entered service in 1998. Production of the Block 1A was planned to continue until 2003 with a US Army total of 625, but further orders were made and filled after 2003. In September 2016, a 10-year life-extension program began on the ATACMS. As a part of this program, the submunition warheads are slated to be replaced with unitary ones.⁶

ATACMS Block 1A Unitary

The Block 1A Unitary is a unitary warhead version of the ATACMS Block 1A missile, using either the 213 kg HE blast/fragmentation warhead from the AGM/RGM-84 Harpoon or the 247 kg HE blast penetration warhead from the SLAM-ER missile to replace the 300 submunitions of the Block 1A. It is now known as the Block 1A unitary missile. The ATACMS Block 1A unitary has been designed to minimize collateral damage and to attack critical target points in all weather. Its 300 km range allows it to attack targets far behind enemy lines and rapid reloading allows for sustained firing. The small size of the missile and the mobility of launch vehicle system allow the missile to be positioned for maximum effectiveness.

Development started in 1999 on the ATACMS Block 1A unitary. Forty-three unitary warheads were ordered in 2000, which were delivered and tested the following year. Orders for the unitary warhead version of the Block 1A missile were first placed in 2000 and tested in 2001. A further 24 Block 1A unitary missiles were ordered in February 2002, and an additional 68 were ordered in February 2004. Some original Block 1 missiles were converted to the unitary warhead design, thus raising the total number of Block 1A unitary missiles to around 280. A 2008 test of a Block 1A unitary missile successfully used the missile to make a vertical dive on a target.⁷ The U.S. Army has announced that it plans to replace all ATACMS missiles with their Long Range Precision Fires (LRPF) missiles beginning in 2018.⁸

ATACMS Block 2

The Block 2, which was terminated in October 2002, was to be the anti-tank version of the ATACMS system. Equipped with guided anti-armor Brilliant Anti-Tank (BAT) guided submunitions or BAT P31 improved submunitions, it was designed for the ‘many-on-many’ approach, deploying multiple submunitions against multiple targets. The system released the Brilliant Anti-Tank (BAT) submunitions over an area and the munitions found and homed in on vehicles. It was intended to attack and destroy moving armored units or stationary missile/rocket vehicles. The missile had a range of 140 km (87 miles) and was to be deployed with a single 268 kg warhead. It was 3.98 m long, 0.61 m wide, and had a launch weight of 1,483 kg. It used a single-stage solid propellant motor. As of 2002, funding for the Block 2 was cut, and the program closed.⁹